Crankcase lubricant for spark ignition engines



FGR SPARK iGb-iiilitlbt ENGENESB No Drawing. Application January 4, 195aSerial No, 452,133

'7 Qlairns. (Cl. 252===1$ The present invention relates to improvedcrankcase lubricants and pertains more particularly to a novelcompounded lubricating oil composition having properties making itespecially adapted for use in gasoline engine crankcase lubrication. Theinvention concerns an improved crankcase oil having several importantproperties which heretofore were not simultaneously obtained in onecomposition.

For the past several years much effort has been expended in theautomobile and oil industries to improve the performance of motor cars.This has been efiected by improvements in engine design and in increasedoctane ratings for gasolines. Also, higher level compounding has beenemployed in crankcase lubricants to promote engine cleanliness and lowwear when the more severe conditions encountered in start-stop citydriving particularly in engines with close-fitting parts which arecritical to these conditions, and reduced clemances between workingparts encountered in modern motor cars. These compounding agents areemployed in greater amounts to combat the deleterious effects of enginedeposits such as piston lacquer and crankcase sludges, which are morecritical problems in the gasoline engines of recent design, as foundparticularly in those of higher compression ratios and smallerclearances. For instance, hydraulic valve lifters commonly are partiallyor completely stuck by deposits and therefore particular attention mustbe given to the crankcase lubricant in order to avoid deposition ofmaterial in the valve litters and the damage resulting from suchdeposits. Widely employed as compounding agents for imparting detergencyand reduced wear characteristics to a crankcase lubricating oil andhence for promoting engine cleanliness are oil-soluble polyvalent metalphenates such as calcium alkyl phenates and oilsoluble metal sulfonatessuch as calcium mahogany sulfonates formed from sulfonic acids derivedfrom petroleum. Commonly, the phenates and sulfonates are employed incombination to reduce wear and deposits.

A primary function of a crankcase lubricant is to reduce friction andthereby to increase the efhciency of the engine operation. With reducedfriction less energy in the form of consumed gasoline is expended inmerely bringing the engine operation up to the point of zero poweroutput. For minimizing friction and, likewise, for ease of starting incold weather, low viscosity oils have been employed. Crankcase oils ofsuch nature have been designated as SAE grades W, W, etc.the suflixindicating that the oil is a winter-grade oil having certain lowviscosities at low temperature for startability in cold weather. Suchlow viscosity oils, however, suffer from the disadvantage of beingconsumed at a higher rate than the higher viscosity motor oils. Theexcessive consumption may result in an oil mileage as low as 5060 milesper quart of oil for certain types of operations. Even some so-calledmulti-graded oils commercially available have oil mileages of one-halfor less than that of SAE 30 grade crankcase oil. Because of such poorconsumption characteristics he oil supply in equipment is required to bereplenished frequently in order to prevent damage to the engine for lackof sufficient lubrication. As a consequence, many motor carmanufacturers in recent years have recommended the use of SAE grade 30oil for maximum oil economy. Thus, the desirable properties of goodgasoline mileage and ease of cold Weather starting have not beenobtained with a crankcase lubricant giving low oil consumptioncharacteristics.

Heretofore various materials, usually polymeric materials, have beenproposed as addends to improve the viscosity index of lubricating oilstocks other than paraifinic oils which have the lowestviscosity-temperature coefficient of uncompounded mineral oils. It hasbeen said that the effect of these so-called viscosity index improversis to give false viscosities and hence the resultant oils are notexpected to give the oil consumption characteristics indicated by theirviscosities as conventionally measured. In other words, the oil would beexpected to be consumed at the rate indicated by the viscosity of theoil alone rather than by the viscosity of the oil compounded with aviscosity index improver. As stated by another expert, it is generallyrecognized that viscosity index improvers have one fundamentallimitation: because they increase the viscosity of the fluid base, theycannot be used to make a high viscosity index liquid with a lowviscosity unless a liquid base of very high volatility can be tolerated.Heretofore it has been believed that the front end volatilitycharacteristics of the base oil controlled oil consumption.

Another problem confronting modern motor car operations resides in thetendency of the engine in the course of use to require a graduallyincreasingly higher minimum octane rating for the gasoline to avoidincipient knocking. This phenomenon of octane rating increase becomescritical with the several very high compression engines now on themarket; for example, with some such engines the octane rating increasesto the point that the highest octane gasoline commercially available isinsufficient to avoid incipient knocking particularly when the engine isbeing forced, such as when climbing a hill.

While heretofore some of these various desirable properties have beenattained to some extent in certain lubricants and others of theseproperties have been attained in other lubricants, one crankcaselubricant has not had all of these properties simultaneously. Indeed, itwas believed that some of the properties, such as low friction, couldonly be attained at the expense of other properties, such as low oilconsumption. Now, in spite of the long expressed desire, the propercombination of materials has been discovered, which results in acrankcase lubricant having all of the desired properties to a sufficientextent.

Accordingly, an object of this invention is to provide a crankcaselubricant which simultaneously imparts the following characteristics toengine operation: low friction and hence resulting high gas mileage, lowminimum cranking temperatures and hence good startability in coldweather, low oil consumption, low engine wear, good engine cleanlinessand relative freedom from engine deposits, and reduced build-up ofgasoline octane rating requirements.

lit was found that the compounding agents commonly used in crankcaselubricants to promote engine cleanliness and low wear could not beemployed without adversely afiecting other desired properties of thelubricant. Likewise, it has now been found, as set forth more fullyhereinbelow, that the other ingredients and the base oil must havecertain characteristics.

The foregoing objects and advantages are obtained by a crankcaselubricant having as its essential components a selected low viscosity,narrow boiling range hydrocarincreased gasoline mileage amounting inshort trip 013-, eration typical of stop-and-go, city driving toanimprove= ment of up to about in gasoline mileage in actual motor carcity'drivingtests; Surprisingly; the oil mileage is not as low as isnormal for'SAE 10W grade oil but hasbeen found to be at least'equivalentto a conventional SAE'30 grade oil: Thus the new lubricant uses lessgasoline per mile without any increase in oil consumption as comparedwith the" best compounded SAE grade motor oil on the market; In; otherwords, the new lubricant is" responsible for direct saving in gasoline,and unexpectedly does' so without-consuming additional lubricant.

Not only is the finding of'concomitance of increased gasolinemileageand'low oil consumption unexpected, but also it is surprising to findthat in. a majority of engine tests with our preferred composition alower oil con sumption is obtained than would be predicted from theusual viscosity measurement of our'final composition. In

fact, our composition meeting the SAE grade classification shows'in sometests a lower oil consumption than a conventional SAE 30 grade oil ofhigh quality and in certain engines even'lower' consumption than an SAE40 grade oil; this result ofthe comparative tests is contrary to theexpected lower oil consumption for the higher SAE grade oil.

Further, our versatile new lubricant with its good detergency and wearcharacteristics is not obtainable with the commonly employed additives"mentioned herein- Such common additives adversely'affect one or Forabove; more of the" desirable properties of the lubricant.

example, the use of polyvalent' metal phenates such as sulfurizedcalcium cetyl-phenate causes a greater increase in viscosity as thetemperature is lowered than is found with the chef the presentinvention; hence, such phenate oils give greater friction at lowtemperatures and consequently result in lower gasoline mileage. Statedanother way, the use of phenates as the detergent in place ofour specialadditive in the new lubricant composition results in a lubricant'whichis' unsatisfactory for efiicient low temperature operation and good coldweather start- 4 stabilized with an oil-soluble alkaline earth metalsulfonate to form a filterable composition; The apparent reactionproduct can also be described as a glycolated metal base or a glycoxide,which may be modified by other reactants as describedhereinbelow. Themetal sulfonate is believed to form micelles in oil solution and as suchefiects the dispersion or solubilization of the glycoxide or modifiedglycoxide.

The glycoxide-sulfonate material can be produced by forming a mixture oflubricating oil, ethylene glycol, an oil-soluble, alkaline earth metalsulfonate and ,an inorganic alkaline earth metal base (i. e., oxides orhydroxides). Suificient heat is supplied to elfect the reaction betweenthe metal base and ethylene glycol before or after the addition of theoil and sulfonate and also after the addition of the oil and sulfonateto remove a substantial portion of the ethylene glycol, i. e.,such asremains uncombined. Solids, such as unreacted metal base, are removed byfiltration. In the initial mixture at least 2,. but not usually morethan 50, mols of ethylene glycol are employed for each mol of inorganicmetal base. The sulfonate dispersant and inorganic metal base areusually incorporated in a sulfonate/metal base mol ratio of about0.1-2:1, an excess of 10% of. the metal base often being added'abovethis amount. The oil is preferably of the same character as the base oilcomponent of the final composition as described hereinbelow and isemployed in suflicient amount to disperse the glycoxide materialandsulfonate. Ordinarily it is not convenient to formconcentratescontaining less thanabout by weight of oil." When a calcium petroleummahogany sulfonate (ca 1000 mol. wt.) and lime are employed, thesulfonate dispersant is normally present in an amount of at leastonepart for each 0.6 part (dry weight basis) of the metal base, expressedas CaO. While ethylene glycol is preferred because of its efliciency ona weight ing. Also, our new'lubricant issuperior to such phenatecompounded crankcase oils in that it gives increased gas mileage. Thus,the choice of compounding agent for good detergency and low wearcharacteristics is critical, because the aforementioned phenatesadverselyatfect the desired properties and the glycoxide-sulfonatematerial is surprisingly free of such adverse effects. Further, theglycoxide-sulfonate material has been found in many in stances to bringabout an increase in the viscosity index of the composition, which efiect is not obtained with the conventional improving agents.

Further, the combination of components results in a lubricantcomposition having a pour point which is lower than, predictable fromthe nature and amounts of the components. For example, a lubricantprepared from a base oil having a pour point of +15'.F., in accordancewith this invention, had a pour point of 45 R, where-.

as other lubricants containing similar amounts of. polymer and base oilhave pour points l0-20 F. higher.

More particularly, the alkaline earthmetal glycoXide al kaline earthmetal sulfonate material is a dispersion of the product of reactionbetween. an alkaline earth metal base and an alkylene glycol saiddispersion in oil being basis, the higher. dihydric alcohols,particularly the vicinal alkane diols of less than '5 carbon atoms canbeemployedon occasion. The alkaline earth metals referred'to above includecalcium and barium, of which the former is normally preferred. Whencalciumglycoxide is' employed, particularly the larger amounts relativeto the sulfonatedispersant, it is preferred that prior'to the removal ofethylene glycol and the filtration, a carboxylic acid or its metal salt(or mixtures) :be addedin an amount so as to yield 0.3 to 1.5 mols ofmetal. salt per mol of calcium glycoxide in order to inhibit gelformation which-hinders filtration and which tends to increase theviscosity ofqthe glycoxide oil concentrate as well as the finallubricant composition. Suita'ble carboxylic acids are those having 1 to3 carbon atoms starting with formic acid and preferably are hydroxycarboxylic acids including carbonic, glycolic and latic acids.Particularly eflicacious is thecombination of an alpha hydroxycarboxylic acid, such as glycolic acid, and a non-hydroxy carboxylicacid, such asformic acid, in about equimolar amounts." These metalcarboxylates, added as salts or formed in situ from the acids, arebelieved to become part of the dispersed material and hence modify thedispersed glycoxide. Thus, the term glycoxide material does not excludethe presence of these metal carboxylates, and the term dispersed metalbase contemplates a dispersion of metal carboxylate as well as metalglycoxide; for convenience, the term glycoxide material in its genericsense will or,-

" dinarily be used.

Normally, the glycoxide-sulfonate material willf-be prepared as aconcentrated oil solution which is 20 to 40 times more concentrated thanthe final lubricant composition. The viscosity of this oil concentrateshould be kept as low as possible; for an oil concentrate containingabout 1000 mM/kg. of total metal the viscosity is preferably below about250 SSU at 210 F., although the viscosity may in some cases be as highas 450 SSU, or as low as 220 SSU or less. It is especially advantageousfor minimizing the viscosity increase due to the addition of agentsother than the methacrylate polymer to incorporate thehereinbelow-described thiophosphate and sulfide inhibitors into saidconcentrate and to subject the resulting mixture to heat treatment,preferably at a relatively low temperature such as 130-150 F. for aperiod of about 2 to 6 hours, prior to combining with the oil componentof the final composition. Such pretreatment of the concentrate has beenfound to yield a final composition having a lower viscosity thanotherwise possible.

In the final lubricant composition, the amount of total metal, bothdispersed metal base (glycoxide and carboxylate) and metal sulfonatedispersant, is from about 20 to 120 millimols per kilogram (i. e.,mM/kg.) of the composition. For optimum detergency and wearcharacteristics consistent with the other desired properties such asminimum formation of pre-ignition promoting deposits for gasoline engineservice, said total metal preferably is above 30 mM/kg. but usually lessthan 60 mM/kg. The mol ratio of dispersed metal as glycoxide andcarboxylates to sulfonate metal in the final composition will generallyrange from .50, preferably at least 1.0, to about 10.0. Moreparticularly, for each mol of metal sulfonate dispersant, there is1.0-10.0, preferably 2-6, mols of metal glycoxide, and 0-40, preferably0.3-1.5, mols of metal carboxylates. In the preferred range of metalglycoxide the mol ratio of glycoxide to carboxylate will be from 1.0 to3.0:1, and preferably about 2:1.

In terms of millimols of metal per kilogram of final composition, andwithin the above foregoing limits as to ranges and ratios, the amount ofdispersed metal base as glycoxide and carboxylates can range from about7 to 110 mM/kg. but is preferably 15-55 mM/kg., and the metal in theform of sulfonate dispersant can be 2-80 InM/kg., but is preferably 3-30mM/kg.

The oil-soluble methacrylate ester polymer preferably has a molecularweight ranging from about 250,000 to 500,000, as determined by lightscattering measurements. These particular polymers not only improve theviscosity index and lower the pour point of the final composition, butalso undergo a peculiar phenomenon during use in the engine. Thesepolymers apparently are capable of suffering reversible molecular weightdegradation in the areas of the engine where they are subjected to highshear stresses. The apparent lowering of the molecular weight of thepolymers and consequent decrease in the viscosity of the lubricantcomposition is temporary, and when the lubricant composition flows awayfrom the zones of high shear stresses to areas of low shear the apparentviscosity of the lubricant is reestablished at a relatively high value.The apparent molecular weight degradation seems to be at least partiallyinduced by shearing action which may cause an actual breakdown of themolecule or micelle or may result in a stretching of a compressedmolecule or a straightening out of a curled up molecule or particle.This effect is especially pronounced with the polymers in the preferredmolecular weight range and is found to a lesser extent with themethacrylate ester polymers having molecular weights as low as 10,000and as high as 5,000,000. The phenomenon of reversibility of theapparent molecular weight degradation has been found to be possessed toa high degree, evidently uniquely so, by the methacrylate ester polymersemployed in combination with the alkaline earth metal glycoxide-alkalineearth metal sulfonate material. Also, the effect may be promoted by thepresence of thiophosphate and sulfide inhibitors. Whatever the mechanismmay be, the phenomenon gives startling results in attaining in onelubricant, inter alia, first, the advantage of low friction at highshear rates with resulting high gasoline efficiency and, second, theconcomitant advantage of low oil consumption. In a preferred embodimentof our new lubricant invention there is obtained both thecharacteristics of a normal SAE 10W grade oil with respect to enginestartability at low temperatures and high gasoline mileage and the 10Woil consumption qualities of a conventional SAE 30 grade oil. Onetheory, not intended to be binding, which may be offered as anexplanation of the outstanding results is that in the areas between thepiston and cylinder walls and in the films within and surrounding thejournals and bearings within the crankcase, the viscosity of thelubricant is sufficiently low at the high shear rates to result in a lowfrictional drag on the rapidly moving parts. At the same time theviscosity of the lubricant is relatively high at the piston ring-grooveinterfacecs where the shear rates are relatively low, whereby the highviscosity minimizes the leakage of lubricant through the piston ringgrooves on into the combustion chamber and thus effects a reduction inoil consumption.

The methacrylate polymers can be designated as poly- (alltylmethacrylates) in which the alkyl group preferably has 8-36 carbonatoms, although alkyl radicals having as little as 6 or as great as 20carbon atoms are not excluded. In general, the alkyl chain length shouldbe sumcient to give the desired oil solubility at the concentrationdesired but not so high as to decrease substantially the viscosity indeximprovement or the reversibility of the apparent molecular Weightdegradation. Suitable polymers are obtained from methacrylic acidesterified with various alcohols including hexyl, octyl, nonyl, lauryl,cetyl, and octadecyl alcohols or mixtures thereof. Mixtures of alcoholscan be derived from various sources, for example, by dehydrogenation ofnaturally-occurring oils like cocoanut oil. Such mixtures are sold underthe names Lorol, Lorol B and Lorol R and are mixtures of straight-chainprimary alcohols ranging from 10 to 18 carbon atoms; one such mixture ispredominantly (about lauryl alcohol along with a small amount of C14alcohol and lesser amounts of C and C alcohols. illustrative linearpolymers are poly(lauryl methacrylate), poly(octyl methacrylate), etc.of various average molecular weights. Such polymers are sold by Rohm &Hass Company under the name Acryloid with various identificationnumbers. Acryloid 710 is understood to be a polymer of methacrylic acidesters of alcohol mixtures predominating in lauryl alcohol. OtherAcryloids are polymers of lauryl methacrylate having different averagemolecular weights or of alkyl methacrylates wherein the alkyl groupaverages from 10 to 16 carbon atoms and is derived from mixtures ofalcohols. Acryloid 710 has an apparent molecular weight based onviscosity increase measurements of 10,000-30,000, while light scatteringdeterminations indicate a weight of 150,000-200,000. A 30% (on anoil-free basis) solution of Acryloid 710 in toluene has a viscosity atF. of centistokes; Acryloid 710 at 1.5 weight percent (on an oil-freebasis) increases the viscosity of a California base oil from 65 SSU to85 SSU at 210 F. Other illustrative Acryloids at 30% concentrations intoluene give the following viscosity measurements: No. 763350 cs.; No.794- 600 cs.; and No. 74790 cs. The various Acryloids are normallyavailable as 40% (dry basis) of polymer dissolved in oil.

The methacrylate polymer is employed in amounts ranging from about 1.5,especially above 2.5%, to 5% by volume of the final lubricantcomposition, and in a preferred embodiment of the present inventionsuficient polymer is added to increase the viscosity of the finalcomposition to 6070 SSU at 210 F. as measured by ASTM Test ProcedureD-88-44. For example, with an oil base having a viscosity of about 40SSU at 210 F. and a viscosity index of about 90, sufiicient polymer of aproper molecular weight is added to bring the viscosity up to about 65SSU, thereby producing in conjunction with the glycoxide-sulfonatematerial a crankcase lubricant having the hereinabove-described idealcharacteristics to a high degree.

The hydrocarbon oil component of the present invention must have certainproperties which are critical for the complete fulfillment of theobjects of this invention.

W havejffoiiiidthat'neither the viedo sity atany specifici" temperaturenor the viscosity index alone is determinative inhelectingthe properbaseoil'. Both iof these factors; must be in certain rangesland, further, toattain all the" desired characteristics or the preferred embodiment theoil must have a minimum boiling point spread. Thus, the base oil has aviscosity ranging from about 5000 to 8000 SSU.:at .F. (determined asnoted below), a viscosity index 01585 120 and a boiling range ofnot':more than about E- difierence between the 10% and 90%points as'idetermined by the ASTM D 1 160 procedure at a pressure of 1 .ofmercury. The viscosity at 0 F. is found in accordance 'with SAE'recommended practice as' 'de scribed in Federal Specification VVL-791c,Lubricants lubricant compositionhaving to an especially high degree thedesired propelties of 'high gasoline mileage, good cold weather enginestarting"characteristics, and low oil con sumptionpcare is taken intheselection of the base oil along with the nature and amount of thepolymer and the glycoxidesulfonate material, which has been foundnecessary to obt ain the desired high quality final lubricantcompositionjbecause of the interdependence of the properties of theindividual components. Thus, the amount and molecular. weight of thepolymer together with the viscosity of the base oil, as well as theglycoxide-sulfonate material, are chosen so that the viscosity at 0 F.for the final composition is less than 12,000 SSU. Also, the finalviscosity index which is dependent primarily on the base oil and thepolymer is selected to give a viscosity for the final composition of atleast SSU but usually less than '70SSU at 210. F. .as measured b ASTMTest Procedure D 8844. Ordinarily the higher the viscosity of the baseoil within the above, stated range, the lower the amount of the. polymerand the'higher its molecular weight will be used to get the optimumviscosities at 0 F. and 210 F. Stated another way, the amount of polymeradded along with the .glycoxide-sulfonate material to the base .oilisnot more than that which raises the 0 F. viscosity. above.1 2,000; SSUbut, while adhering to this limitation, is the maximum for raising the210 F. vis- V cosity to 6'0 70 SSU. The higher molecular Weight polymers within'the'rangespecified above give on an equal Weight basis thegreater viscosity increase at 210 F. From" a viscosity index standpoint,the oils having the lowestviscosity index within the above range requirethe use of base oilshaving the lower 0 F. viscosity and the greater"amount of polymer. The foregoing directions are given byway of exampleto enable one skilled in the artto readily select the proper proportionsand properties within the specified ranges for theindividual componentsinorder to obtain a final crankcase lubricant composition which meetsthe SAE classifications for both 10W and 30 grade oils. 1

Thethiophosphates which are preferably incorporated in the new crankcaselubricant of the present invention are generally polyvalent metalsalts'of esters of thiophosphoric acids wherein the ester radicals canbe hydrocarbon radicals such as alkaryl or alkyl groups which may be thesame or difierent. Particularly efiicacious are mixed alkyl estershaving less than 4 carbon atoms in one alkyl group and 6 to 18 carbonatoms in the 'other group. Although various metals such as the zincsalts of butyl hexyl dithiophosphoric acid, methyliii hexylqithiophespherieacid; butyl methylisobutylcarbinol dithiophos'phbric'acidfdioctyl 'dithioph'osphoric acid; di

hexadecyl"'dithiophosphoric acid, dibutylphenyl dithiophosphoric acidgidicetylphenyl dithiophosphoric acid, etc; 'T hethi'ophos'phate'sfmay be used in-amountsasdowi'as' .05 andup"to"about"5% by weight althoughamounts ranging ifroirro l to 2%'are'pref'err'ed; In terms of milliniol's"per kilogram 'of nietali the"thiophospha'tes -are mostdesirably present 1 in the 'finalcompositioirin' con centrations'"bf"from "3 rnM/kg; Y to "about -10'm'M'7kgfi Suitable" sulfur inhibitors are the-various oil=sol1ible'sulfur antioxidants" such-"as aliphatic polysulfides, e:*g;, dihexadecyltetrasulfidey multi-bridged' thioalkyl." com H pounds, suchfas:afef'forrnedfby reaction of polychlorinated' wax fahdsddiiim polysulfideand" as exemplified further in U. S'Patent 2,514,625; sulfurizedolefin'ssuch' as sulfurizeduerpenes," reaction-products of; terpenes andphosphorusisulfides such" as P S etcr Preferably, the'sulfi'deinhibito'fisamen-aromatic com'poundl Gen erall'y, the" sulfideinhibit'or will be used in amounts from* 0.05% 11 5403 or 4%,preferably'from about 0.1% to" 1.5% byweig'ht of the final'lubricantcomposition.-

To illustrate 'furtherthe present invention'; there are presentedhereinbelowexamples" of'preparations of vari out formulations and theresults of numerous 'tests thereon:

Exdm p'leL A series of formulations were prepardi' with a base oilderived by solvent refining ofa Cali fornia crude and having fthfollowing properties:

To this base oil was added" in each for1 i1ulatiori 6.4%"

(40% solution in oil) of A cryloid 7 10 plus 0.25 7 or a sulfurizeddiparafiin sulfide; 6 mM/kg. off a 'ziiic cetylphenyl dithiophosphate"and the various amounts' as' indicated below o f a glycoxide-sulfonatematerial." This] last was prepared as an oil: concentrate'as fouowsi 75.7 grams of ethylene glycol and 22 grams ofiin'ief were admixedandthenito the admixture was'added 10.8 rams of glycolic acid, of formicacid, roogtafiis of calcium mahogany sultonate along with 200grains-mineral oil. The resultingi mixture was heated to efiect:thereaetionandalso to removeunreacted glycol as well as water of reaction.Aft'er filtration, the oil concentrate contained 4.5 by weight ofcalcium (calculated as calcium metal) and a visc osity of 250 SSU at"210 F. Sufiicient of this oil concentrate was added to portions of theabove-described compounded base oil to give 28 mM/kg., 39 mM/kg., andmM/kg as total metal,

of the glycoxide sulfonate' material for compositions A,- B and .C,respectively.-

These compositions had the i. properties shown in Table I.-

The data in Table I illustrate that compositions A, B and C withdifferent amounts of the glyooxide-sulfonate material satisfy therequirements for both SAE grade 10W and SAE grade 30 oils. The data alsoshow the excellent viscosity indices and low pour points obtainable forcompositions of the present invention.

Example 2.T illustrate the present invention further, preparations weremade of compositions similar to composition B in Example 1 except thatin the case of composition D, 6.8% (40 oil solution) of Acryloid 710 wasemployed and in the case of composition E, a zinc mixed dialkyldithiophosphate was substituted. The properties of these compositionsare tabulated as follows:

Table II Viscosity (SSU) at ASINI Compo- Vis. pour pt. ASTM sitlon indexF. color 100 F. 210 F. 0 F.

Likewise, as indicated by the foregoing data, compositions D and E havehighly satisfactory properties.

Example 3.-For comparison, formulations were prepared similar tocomposition A of Example 1, except that in place of theglycoxide-sulfonate material, there was substituted: for composition F,10 mM/kg. of a calcium petroleum mahogany sulfonate plus 20 mM/kg. of asulfurized calcium cetyl phenate; for composition G, 15 mM/kg. of saidsulfonate and 35 mM/kg. of said phenate; and for composition H, 10mM/kg. of said These data illustrate that the substitution of thephenate sulfonate combination for the glycoxide-sulfonate materialadversely aitects the viscosity index and raises the viscosity at 100 F.and at 0 P. so that the oils do not satisfy the requirements for an SAE10W grade oil.

Example 4.-A crankcase lubricant meeting the requirements for SAE 10V],20W and 30 grade oils was prepared with the following composition byweight: 87.5% of the selected base oil described below, 6.8% (40% oilsolution) of Acryloid 710, and 5.7% of an oil concentrate which had beenpreviously heat-treated as described hereinabove and which containedsufiicient of each agent to give the following amounts in the finalcomposition: 40mM/kg. of the glycoxide-sulfonate material described inExample 1, 6 mM/kg. of zinc dicetylphenyl dithiophosphate and 0.25% or"sulfuriz'ed diparar'hn wax-sulfide. The base oil was the same as thatdescribed in Example 1. The resulting lubricant had the followingphysical properties: viscosities of 301 SSU at 100 F, 62.6 SSU at 10 210F., and 9000 SSU at 0 F.; a flash point of 425 F., a viscosity index of141, and an ASTM pour point of -45 F. This lubricant will give in anengine operating at 32 F. a cranking speed 54% greater than the speedobtained in the same engine at the same temperature with a conventionalSAE 30 grade lubricant.

Example 5.The gasoline and oil mileage characteristics of the crankcaselubricant composition of Example 4 were compared to those of a referenceoil in several hundred thousand miles of road test in a fleet of taxisand two fleets of passenger cars. In these tests all the vehicles wereoperated alternately with the test oil for one drain period and then thereference oil for a drain period, the cycle being repeated as many timesas possible during the test. The reference oil was a conventional heavyduty compounded SAE 30 grade motor oil. The taxi fleet averaged 3500miles of driving per month per vehicle in predominantly city trafficdriving with an occasional highway trip; cold starts were limited to oneor two per operating day and average engine temperatures were F. and F.for crankcase oil and jacket coolant, respectively. Passenger car fleetA averaged more than 1000 miles per month driving in relatively opencountry at relatively high speeds and ambient temperatures. The cars offleet B were operated predominantly in city traflic on short trips andexperienced a relatively large number of cold starts per month, thevehicles averaging 490 miles of driving per month. The following tablesummarizes the results of the fleet taxis:

Table I V Ave. oil milo- Ave. gas mlle- Percent 1mage, miles! age,miles/ provernent Ave. quart gallon Fleet total test, miles Ref. 1 TestRel. Test Oil Gas oil t-il oil oil milemile- E age age 589 650 ll. 912.4 11 4 758 789 15. 5 16. 2 4 5 751 911 11.0 12. 9 2D 17 Example6.Another series of tests were carried out with heavy duty truckspowered by General Motors engines which were used in long distancegasoline hauling in the lower San Joaquin Valley accumulating mileage ofapproximately 10,000 miles per month under high-speed, high-loadconditions. The crankcase lubricant composition of Example 4 was used asthe test oil in comparison with conventional compounded diesel enginecrankcase lubricating oils of SAE 30 and SAE 40 grades.

The average oil mileage for these tank trucks when operated with thetest oil of the present invention was 42% greater than that observedwith the SAE 30 reference oil, and 21% greater than that observed withthe SAE 40 grade reference oil.

Example 7.--" he improvement in power output by the use of the presentlubricants was measured in a chassis dynamometer with 2. i953 Cadillac,a 1953 Chevrolet power glide and a 1952 Plymouth. The test oil was thecrankcase lubricant composition of Example 4, and the reference oil wasa c 'zventional heavy duty compounded SAE 30 grade motor oil. Under fullthrottle maximum power operation an improvement of 7% was observed inthe Cadillac, 4% in the Chevrolet, and 3% in the Plymouth.

The increase in power observed in the chassis dynamorneter test was alsodemonstrated on the road in the Cadillac and Chevrolet by a 5% reductionin time required to accelerate from 0 to 60 miles per hour when the testoil of the present invention was used in place of the reference SAE 30grade oil.

Example 8.-Two California Highway Patrol car's used were brought to thechassis dynamometer directlyfrom' 1110 service and no tune-up ormechanical work was done on the car's immediately prior to or after thetests. The oil in the cars as received was drained-and replaced "-withreference oil; The maximum speed was determined. Comparative tests'werethen run by'draining tho-engine crankcase and filter and refilling with"the test oil. The test was repeated.

The'maximum' relative speed of the 1953 Oldsmobile showed an increase'of4.5 miles per hour and the 1952 Oldsmobile an increase of 5.5 miles perhour. "The horse power curves showed an increase in power over theentire range tested for both cars when using the'test oil. Thisimprovement in horsepower would result in faster 'acceloration to topspeed as well as an increase in the top speed;

Example 9.''Another series of tests were conducted under'city trafficdriving conditions wherein the car' was driven four trips daily for adistance of 3 /2 miles over a specified route. One-trip was made in lateafternoon and the car parked overnight. The next trip was made in theearly morning and the car parked until noon, at which time a round tripwas made with one-half hour of parking at the terminus. This cycle wasrepeated for... three days on the test oil and then for three days onthe reference oil. The test'oil was a lubricant composition of Example 4and the reference oil was a conventional heavy duty compounded SAE 30grade oil. The improvements, due to the use of the test oil, in gasolinemileage for the several tests and with difierent drivers ranged from 8%to 17%.

Example 10.The lubricant composition of Example 4 a was tested forits'performance from the standpoint of maintaining engine cleanliness ina standard 40-hour, FL-Z Chevrolet engine test using a low gradegasoline especially prone to cause engine deposits, the conditions beingthose defined in the FL-2 Test Procedure described in the June 21, 1948,report of the Coordinating Research Coun cil on Engine Test C. R. C.FL-2, entitled Research Techique for Determining the Effect of Fuelsand/or Lubricants on Formation of Engine Deposits During Mod-' erateTemperature Operation. This procedure requires the maintenance of ajacket temperature of 95 F. and a", crankcase oil temperature of 155 F.at 2500 R. P; M. and 45-brake horsepower for 40' hours, and thereforeclosely, and reproducibly, simulates the relatively cold engineconditions which are normally experienced in city driving. At the end ofthe test the engine was dismantled and the amount of engine deposits onthe piston determined as follows: Average piston rating was obtained byindividually rating (on a scale of- 0-10 representing the absence of anydeposit) the amount of deposit on each piston skirt and averaging theindividual ratings so obtained for the various pistons. In a likemanner, varnish ratings were obtained for each of the rocker arm cover,the push rod cover, the cylinder wall, and the oil path. Similarly,sludge ratings (on the same scale) were obtained for the rocker armassembly, the rocker arm cover plate, the push rod cover plate, the oilscreen, and the oil pan. These ten difierent ratings were added to givea total engine rating. Under the conditions of this test an over-allengine rating of above is indicative of satisfactory performance, aconventional heavy duty compounded-SAE 30-grade motor oil giving anengine rating of about 80. The total engine'rating obtained for thetest' oil of the present invention'was' 81.8, indicating that 75 Example-1 1.-Theeifectivenes s of the lubricant com position of Example 4 incontrolling hydraulic valve hfter deposits was measured 'in aChevroletpower glide ellgine operated in accordance with the EX-Z TestProcedure of the Coordinating Research'Council as reported intheSeptember 1952 report, entitled Lubricating Enginei-Test 4 Designed toSimulate Deposits in Stop and Go Field Sewice latter purpose thedegreeof discoloration of the' -plunge of thehydraulic valve litter isused as are basis-:fdr

comparison; An oil compounded with diesel -engine -lubri cating oil typecommerciahadditiveto'a level equivalenta' to-Series I lubricants (i. e.;Army Specification --2'104B,

Supplement I) was used as a high standard of 'comparisonpi,

this reference oil permitted theformation of-a. ligh't'gray?discoloration while 1 dark gray 'discolorations are observed withconventional heavy duty compounded'motor oils The 'new' and improvedcrankcaselubricant compositionv of Example 4 was equivalent indegreeof'discoloration of highly compounded Supplement I lifter plungersto the lubricant.

Example 12.The Standard' L-4 Chevrolet -engine-test" described in acoordinating Research Council circular,

entitled 'Test Procedure for Determining Oxidation-Chin 5 acteristics ofHeavy Duty Crankcase Oils, was employed? with a test oil ofthecomposition set forthin Ex ample 4 above. This test measures the controloffhigh: temperature" deposit formation and oxidation stabilityof" the'oil. Thetest procedure 'is to run a Chevrolet engine for 36 'hoursat ajacket temperature'ofZOO 'F., ;and a sump temperature of 280 F. Bearingsarelweighed before" andafter the test and the average bearihgweight-Jossis recorded as the corrosion. Ratings of the varnish andsludge are madefor the various parts,-andIa total engine rating determined therefrom,as inthe FL-Z Chevroleten gine test described in Example 9. p

The test results were a total engineratingaof 98."4*and-- a copper-leadbearing weight loss of 55- mg., per bearingil Example 13.A lubricantcomposition prepared- -in ac="- cordance with Example 4 was evaluated inaPlymouth eh gine operated for hours'at F. oil temperatureand F. jackettemperature at 2500 R. P. M. and 25- brake horsepower. This procedureclosely simulates taxicab service conditions. mined by micrometermeasurements before and after the testat the top, bottom and severalintermediate points} "and micrometer measurements were also used todeter mine the top ringside clearance increase. The results of the testwere as follows:

' Top ring Cylinder side clear- Oylinder wear, shoe inlnches crease,inches 1- -0. 0001 0. 0000 2 0. 00005 0. 0003. I 3-- 0.0000 0. 0005' 40. 0000 0. 0002 5 0. 0001 0.0000 s 0. 00015 -0. 0007 Avera e 0. 0000 0.00005 This test is a96 hour cycling test enrployedflo evaluate lowtemperature deposits -and to} measure sth c' effectiveness of oils incontrolling lifter deposits. FOIthJS The cylinder wear wasdeterasaaaeofor all such parts recorded. The results of the test were as follows:

Example 15.-A Plymouth road test car equipped with a radioactive toppiston ring was employed in two series of comparative tests. The amountof ring wear is determined by the amount of radioactive iron dispersedinto the circulating lubricant. In comparative tests, a lubricantcomposition prepared in accordance with Example 4 gave in 1260 testmiles an average ring wear rate of 0.0048 mg. of iron per mile ascompared to a Wear rate of 0.0054 mg. over 1144 test miles for aconventional heavy duty compounded SAE grade 30 motor oil.

Example 16.-A series of determinations were made of the effect on octanerequirement of a 1952 Plymouth by the use of the lubricant compositionof Example 4 as the test oil and for comparison a conventional heavyduty compounded motor oil as a reference. These were carried out using astandard road octane requirement test conducted in accordance with theprocedure outlined in Coordinating Research Council Designation E-1-748,entitled Research Technique for Determination of Octane NumberRequirements of Vehicles on the Road. This test is conducted on a seriesof reference fuels and ascertains the octane number of the fuel requiredfor incipient knocking of the engine over a standard road course withinthe normal speed range of the vehicle. For the purpose of the test, thefuel line of the engine is disconnected at the suction side of the fuelpump and a special 9&5 inch line run into the cab of the car where theprimary reference fuels are carried.

The test was started with the car showing an odometer reading of 11,700miles. After filling the crankcase with the test oil, the car was runfor 800 miles with a standard premium gasoline which was used throughoutthe subsequent tests. The octane requirement measured as described abovewas 75 at the end of the SOD-mile period. Thereafter, the car was drivenfor 1122 miles with the reference oil at the end of which period theoctane requirement was found to be 80. Following this, the car was thendriven 850 miles with the test oil and the octane requirement dropped to75.

Example 17.ln another series of tests, eight Plymouths in a taxicabfleet were operated for approximately 14,000 miles, all on the samegasoline. The test oil and reference oil of Example 16 were used in fourcars each. At the end of the period, the octane requirement of all thecars was determined in accordance with the method referred to in Example16. It was found that the average octane requirement of the cars usingthe test oil Was four numbers lower than the average requirement of thecars using the reference oil.

Example 18.Another formulation was prepared with a base oil derived bysolvent refining from an East Texas crude and having the followingproperties: ASTM viscosities of 139 SSU at 100 F. and 42.4 SSU at 210F., a viscosity index of about 99, a flash point of 440 F. and

A. P. l. gravity of 32.2", and ASTM D-1160 distillation points at 1 mm.of mercury of 370 F. at 10% and 458 at 90%. A lubricant compositioncomposed of 07.3% of this base oil, 6.5% of the methacrylic polymersolution used in Example 4 and 5.7% of the oil concentrate employed inExample 4 had the following properties: ASTM viscosities of 62.1 SSU at210 F., 291 SSU at 100 F. and 7500 SSU at F., a viscosity index of 143and a pour point of 45 F. This indicates that 14% With the higher 10%distillation points, i. e., above about 350 F, the spread between the10% and points can be greater such as up to 90, provided that theviscosities of the polymer-containing lubricant are in the specifiedranges.

This lubricant composition gave a total engine rating of 98.4 and abearing weight loss of 65 mg. per bearing in the standard L-4 Chevroletengine test referred to in Example 11. Also, this oil gives improved oiland gas mileage when compared to a conventional compounded heavy dutySAE 30 grade motor oil.

Example 19.A variation of the lubricant composition of Example 18 wasprepared by using as the base oil a solvent refined oil from mixedmid-continent and coastal crudes. Such base oil has ASTM viscosities of139.5 SSU at F. and 42.5 SSU at 210 F, a viscosity index of about 100,flash point of 415 F., a pour point of 0 5., A. P. I. gravity of 32.1,and ASTMD1160 distillation points at 1 mm. of mercury pressure of 372 F.at 10% and 455 F. at 90%. A lubricant composition of this base oil withthe remaining components the same as in Example 18 had the followingproperties: ASTM viscosities of 62.2 SSU at 210 B, 288.4 SSU at 100 F,and 8000 SSU at 0 F., a viscosity index of 144, a flash point of 435 F.and a pour point of -45 F.

This lubricant composition gave a total engine rating of 99.4 and abearing weight loss of 61 mg. per bearing in the standard L-4 Chevroletengine test referred to in Example 11. Also, the lubricant gave oil andgas mileages superior to conventional compounded SAE 30 grade motor oil.

While the lubricant composition of the present invention essentiallycontains the selected hydrocarbon base oil component, theglycoxide-sulfonate material and the methacrylate polymer and preferablyin addition contains the thiophosphate and sulfide agents describedhereinabove, the resulting composition with its outstanding performancecharacteristics will not ordinarily need further agents. However, it iswithin the contemplation of the present invention, in some instancesand/ or for special purposes, to incorporate in the composition otheragents such as extreme pressure agents, blooming agents, oilinessagents, foam inhibitors, dyes, other agents which affect the viscosityindex or pour point, corrosition inhibitors, etc.

We claim:

1. An improved gasoline engine crankcase lubricant which meets theviscosity requirements of an SAE 10W oil at 0 F. and the viscosityrequirements of an SAE 30 oil at 212 F. consisting essentially of thecombination of (a) a hydrocarbon lubricating oil having a viscosityranging from 5,000 to 8,000 SSU at 0 E, a viscosity index of 85 to and aboiling range of not more than a 50 F. difference between the 10% and90% boiling points as determined by the ASTM 13-1160 procedure at apressure of 1 mm. of mercury, said oil comprising at least 85% of thefinal composition of the lubricant, (b) 2.5 to 5% by volume of anoil-soluble, alkyl methacrylate polymer having alkyl groups of from 6 to20 carbon atoms and a molecular weight between 100,000 and 500,000, asdetermined by light scattering measurements, the viscosity and viscosityindex for said hydrocarbon oil and the amount and molecular weight ofsaid polymer being such that the final composition has viscosities ofless than 12,000 SSU at 0 F. and 60 to 70 SSU at 210 F., (c) 30 to 60millirnols per kilogram of an inorganic metal base substance consistingof a dispersion of the product of reaction between an alkylene glycol ofless than 5 carbon atoms and an alkaline earth metal base selected fromthe group consisting of oxides and hydroxides, said dispersion beingstabilized in oil With an oil-soluble alkaline earth metal sulfonate,the ratio of metal as dispersed metal base substance to metal assulfonate dispersant ranging from 1.0:1 to about 10:1, said reactionproduct being obtained by forming a mixture containing said metal baseand said glycolin-a ratio ranging from -2 to 50 mols-.-

of glycol for each mol of said metal base. and heating said I mixturefor a suflicient time to effect the reaction between glycol and metalbase, (d) 0.1 to2% by weight of an oil-soluble polyvalent metal salt ofan ester of thiophos phoric acid, and (e) 0.1 to 1.5 by weight of anoil-soluble aliphatic polysulfide antioxidant.

2. The lubricant of claim 1 whereinsaid alkaline earth metal in theinorganic metal base substance and in the sulfonatedispersantis calcium.

3. The lubricant of claim 1 wherein said polyvalent metalsalt of .anester of thiophosphoric acid is a zinc salt.

4. An improved gasoline engine crankcase lubricant which meets theviscosity requirements ofan SAE 10W oil at 0 F. and-the viscosityrequirements of an SAE oil at 212 F. consisting essentially of thecombination of '(a) a hydrocarbon lubricating oil having a viscosityranging: from 5,000 to 8,000 SSU at 0 F., a viscosity index of 85 to 120and a boiling rangeof not more. than a F. difierence between the-10% and90% boiling points as determined by the ASTM D-1160Proceded at apressure of 1 mm. of mercury, said oillcomprising at least 85% oftheufinal composition of the lubricant, b) 2.5 to 5% by volume of anoil-soluble, alkyl methacrylate polymer having alkyl groupsof from 6to20 carbonatoms andka molecular weight between 100,000 and 500,000, asdetermined by light scattering;

measurements, thefviscosity and viscosity index for said hydrocarbon oiland the amount and molecular weight'iof 30 said polymer being such thatthe final compositionhas.

viscosities of less.than 12,000 SSUat 0 'F. and to 7O SSU. at 210 FL,(c) 30 to, "millimols'per kilogram of .metal base'material' stabilizedin oil with anloil-soluble alkaline earth metal sulfonate, the ratio ofmetal as dispersed metal base material to metal 'as sulfonate dis-nMotor Oils? by Georgi, Reinhold Pub. Co., 1 95,0,-

persant ranging from 1.0: 1. to about 10:1, said metal base I materialconsisting of (1) the product of reaction between)from=fl1e:group;consisting;of oxides-and. hydroxides,- and (2) analkaline earfla metal salt of an organic carboxylic acid having 1 to 3carbon atoms, and there being present in ;the lubricant composition-foreach mol of sulfona-te 1 dispersant 1 to "10 mols-ofisaidreactionproduct and0 to 4 mols of saidcarboxylic acid salt, saidreaction product being 1obtained by forming a mixture-containing saidmetal base and said glycol in-a ratio ranging from 2 to 3 50 mols ofglycol for-each rnolof said metal base and heatingsaid-mixturefor as'uflicient time to effect the J reaction betweenglycol-and metal-base,(d) 0.1 to 2% by weight of an oilsolublepolyvalent metal salt of anesterof thiophosphoric acid, and (e) 0.1 to 1.5% by weight, of anoil-solublealiphaticpolysulfide antioxidant. 5. The composition of claim, 4 whereinis present for eachxrnol ofrsulfonatedispersant 2.t0 6 mols of saidethylene glycol reaction product and 0.3 to 1.5 mols of carboxylic acid.

6. The lubricantof claim, 4.wherein said alkaline earth metal invtheinorganic metal base substance and in the 'QTHER'I REFERENCES pages276 ancl'2 77 pertinent. j I j I I Ind. & Eng; Chem;, ol. .45; No.7,'J11Iy 3,pages ethylene glycol and: an alkaline earth'metalbaseselected 1501'to 1508.. I

1. AN IMPROVED GASOLINE ENGINE CRANKCASE LUBRICANT WHICH MEETS THEVISCOSITY REQUIREMENTS OF AN SSAE 10W OIL AT 0*F. AND THE VISCOSITYREQUIREMENTS OF AN SAE 30 OIL AT 212*F. CONSISTING ESSENTIALLY OF THECOMBINATION OF (A) A HYDROCARBON LUBRICATING OIL HAVING A VISCOSITYRANGING FROM 5,000 TO 8,000 SSU AT 0*F., A VISCOSITY INDEX OF 85 TO 120AND A BOILING RANGE OF NOT MORE THAN A 50*F. DIFFERENCE BETWEEN THE 10%AND 90% BOILING POINTS AS DETERMINED BY THE ASTM D-1160 PROCEDURE AT APRESSURE OF 1 MM. OF MERCURY, SAID OIL COMPRISING AT LEAST 85% OF THEFINAL COMPOSITION OF THE LUBRICANT, (B) 2.5 TO 5% BY VOLUME OF ANOIL-SOLUBLE, ALKYL METHACRYLATE AND A MOLECULAR WEIGHT BETWEEN 100,000AND 500,000, AS AND A MOLECULAR WEIGHT BETWEEN 100,000 AND 500,000, ASDETERMINED BY LIGHT SCATTERING MEASUREMENTS, THE VISCOSITY AND VISCOSITYINDEX FOR SAID HYDROCARBON OIL AND THE AMOUNT AND MOLECULAR WEIGHT OFSAID POLYMER BEING SUCH THAT THE FINAL COMPOSITION HAS VICOSITIES OFLESS THAN 12,000 SSU AT 0*F. AND 70 SSU AT 210*F., (C) 30 TO 60MILLIMOLS PER KILOGRAM OF AN INORGANIC METAL BASE SUBSTANCE CONSISTINGOF A DISPERSION OF THE PRODUCT OF REACTION BETWEEN AN ALKYLENE GLYCOL OFLESS THAN 5 CARBON ATOMS AND AN ALKALINE EARTH METAL BASE SELECTED FROMTHE GROUP CONSISTING OF OXIDES AND HYDROXIDES, SAID DISPERSION BEINGSTABILIZED IN OIL WIRH AN OIL-SOLUBLE ALKALINE EARTH METAL SULFONATE,THE RATIO OF METAL AS DISPERSED METAL BASE SUBSTRATE TO METAL ASSULFONATE DISPERSANT RANGING FROM 1.0:1 TO ABOUT 0:1, SAID REACTIONPRODUCT BEING OBTAINED BY FORMING A MIXTURE CONTAINING SAID METAL BASEAND SAID GLYCOL IN A RATIO RANGING FROM 2 TO 50 MOLS OF GLYCOL FOR EACHMOL OF SAID METAL BASE AND HEATING SAID MIXTURE FOR A SUFFICIENT TIME TOEFFECT THE REACTION BETWEEN GLYCOL AND METAL BASE, (D) 0.1 TO 2% BYWEIGHT OF AN OIL-SOLUBLE POLYVALENT METAL SALT OF AN ESTER OFTHIOPHOSPHORIC ACID, ANC (E) 0.1 TO 1.5% BY WEIGHT OF AN OIL-COLUBLEALIPHATIC POLYSULFIDE ANTIOXIDANT.